4 glue sticks cost $7.76. Which equation would help determine the cost of 13 glue sticks?
Answer: There are several equations that could help determine the cost, each with a slightly different approach. We know the cost of 4 glue sticks. We want to know the cost of 13 glue sticks. We can write the numbers of glue sticks as a proportion: $\dfrac{4}{13}$ We know 4 glue sticks costs $7.76. We can let $x$ represent the unknown cost of 13 glue sticks. The proportion of these costs can be expressed as: $\dfrac{\$7.76}{x}$ The cost changes along with the number of glue sticks purchased, and so the two proportions are equivalent. $\dfrac{4}{13} = \dfrac{\$7.76}{x}$